vSphere High Availability. VMware High Availability has been transformed into a cloud-optimized availability platform.

The vSphere HA feature is one of the most interesting to myself. Here are some of the reasons why I’m excited about this:

App Aware API. This is the same API that has been used by Neverfail’s vAppHA and Symantec’s ApplicationHA products. Now with 5.0, this API is publicly available. This means anyone can craft a solution that allows for the monitoring of a application and interfacing with vSphere HA to restart the VM. Couple this with the new vSphere Web Client’s ease of extensibility and you have the potential to do some great things.

Ever had DNS resolution cause you issues when using vSphere HA? With 5.0, all dependency on DNS for vSphere HA has been removed!

IPv6 is now supported.

Logging. There have been a lot of improvements to the log messages with vSphere HA. This was done to make the log messages more descriptive than ‘unknown HA error’ and should help with identifying configuration issues.

Several user interface enhancements. Now you can see more detailed state information about the hosts in your cluster and what role they play with vSphere HA.

However, all of these pale in comparison to the changes made to the vSphere HA infrastructure and the addition of the use of heartbeat datastores.

The changes to the vSphere HA infrastructure now eliminates the primary/secondary constructs that existed in previous versions of vSphere. Replacing that is a master/slave model. In this model, one of the hosts is designated as a master, while the other hosts are designated as slaves. The master coordinates most of the activities within the cluster and relays information to and from vCenter. I’ll be posting several more articles on how this works in detail later.

For now though, the reason why this is so great is that you no longer have to worry about details such as what hosts act as your primary nodes and which ones act as secondary nodes. If you are installing vSphere HA in a blade chassis or making a stretched cluster, this is excellent news for you!

Heartbeat datastores is a feature that allows vSphere HA to utilize the storage subsystem as an alternate communication path. Using heartbeat datastores allows vSphere HA to do things like determine the state of the hosts in the event of a network failure of the management network. Which brings up another enhancement to be excited about: management network partitions are now supported in 5.0!

I’ll be covering a lot of this in much more detail in the near future. This should give you a good overview of what you should be looking forward to with the vSphere 5.0 release!